Method and arrangement for controlling an internal combustion engine

ABSTRACT

A method and an arrangement for controlling an internal combustion engine is suggested wherein, in at least a first operating range, a lean air/fuel mixture are pregiven and, for a power command from the driver (for example, in transient operating states or in the vicinity of the full load range) a switchover to a stoichiometric mixture takes place; during the transition, the torque change (caused by the change of the air/fuel ratio) is essentially compensated by correspondingly influencing the air supply to the engine.

BACKGROUND OF THE INVENTION

A method and arrangement for controlling an internal combustion engineis disclosed in U.S. Pat. No. 5,014,668. There, the internal combustionengine is driven in the lower and mid load ranges with an excess of air,that is, with a lean air/fuel mixture (λ>1). If the accelerator pedalposition signal exceeds a pregiven position threshold value in the upperload range, then a throttle flap (that is, the air supply to the engine)is adjusted in such a manner that an essentially stoichiometric mixture(λ=1) is maintained. With this measure, the advantages of an enginedriven with a lean mixture can be used in the part-load range without itbeing necessary to accept a loss of power in the upper load range. Inthis way, a reduced toxic-substance emission and a reduced consumptionof fuel is obtained. The adjustment of the throttle flap in order topass from operation with a lean mixture into an operation with astoichiometric mixture or vice versa is undertaken slowly within apregiven time span in order to exclude jumps in torque. With this slowtransition, high loads of toxic substances can arise in the exhaust gasso that a slow adjustment of the throttle flap in some operating statescan have unwanted consequences.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide measures accordingto which the transition from lean operation into the stoichiometricoperation and vice versa takes place while reducing the toxic-substanceemissions and while avoiding jumps in torque.

In addition, it is a target of the procedure of the invention toindicate under which conditions a change of the type of operationappears suitable, that is, for example, in which operating state the oneor other mode of operation is to be selected and on the basis of whichsignals or signal traces the transition is to be detected.

Furthermore, in the known state of the art, the control of the throttleflap is undertaken in all operating ranges via an electrical path, thatis, a so-called electronic accelerator pedal system is utilized. Such acontrol system is very extensive so that the complexity and the cost torealize the control of the engine can be considerable.

According to a further aspect of the invention, a control system istherefore provided for an internal combustion engine for a leanoperation in first operating states and a stoichiometric operation insecond operating states which is less complex and nonetheless exhibitsan adequate influence on the supply of air to the engine for asatisfactory transition from the lean region into the stoichiometricregion.

DE 4,111,078 A1 provides, for traction control, a second throttle flapwhich is electrically actuable from its fully open position to itsclosed position. This is in addition to the main throttle flap in theintake system of the engine which is actuable by the driver via amechanical path. The second throttle flap is, as a rule, in the fullyopen position and is actuated in the closing direction to reduce thepower of the engine when there is slippage at the drive wheels.

With the procedure of the invention, a control system for an internalcombustion engine is provided wherein a transition from a mode ofoperation with a lean mixture composition in first operating states to amode of operation with a stoichiometric mixture composition in secondoperating states is ensured without a jump in torque and increasedemissions of toxic substances.

It is especially advantageous that, with the procedure of the invention,an operation of the internal combustion engine with a lean mixturecomposition is possible in large load ranges. It is further advantageousthat, at increased power requirement (for example, in the accelerationphase, during transient operation or in the upper load range of theengine), a comfortable rapid switchover to a stoichiometric mixturecomposition takes place; whereas, for reduced power requirement, acorresponding transition into the mode of operation with a lean mixturetakes place.

Furthermore, and in an advantageous manner, a possibility is provided tointervene in the air supply to realize the procedure according to theinvention which can be provided without great complexity and whichinfluences the air supply to the engine to a sufficient extent torealize the transition.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the drawingswherein:

FIG. 1 is an overview block circuit diagram of a control for an internalcombustion engine wherein the procedure of the invention is realized;

FIG. 2 shows an overview block circuit diagram of the control unit forrealizing the procedure of the invention;

FIGS. 3a to 3d show respective operating parameters plotted as afunction of time for an exemplary operating situation;

FIG. 4 shows a flowchart as an example realizing the procedure of theinvention as a computer program.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

In FIG. 1, a preferred embodiment of a control arrangement for aninternal combustion engine is shown wherein the procedure of theinvention is realized. The engine 10 includes an air intake system 12and an exhaust-gas system 14. A first throttle flap 16 is mounted in theair intake system 12 and is connected via a mechanical connection 18 toan operator-controlled element 20 actuated by the driver, namely, anaccelerator pedal. The accelerator pedal 20 or the throttle flap itselfis biased against its rest position by means of a spring in a mannerknown per se. In addition, a second throttle flap 22 is mounted in theintake system. The second throttle flap 22 is connected via a mechanicalconnection 24 to an electric motor 26. The throttle flap 22 is biasedinto its fully open position via a spring 28. Furthermore, one orseveral injection valves 30 for metering fuel are provided. A controlunit 32 receives a measure for the air supply to the engine from asensor 34 (air quantity sensor, air mass sensor, pressure sensor orthrottle flap position sensor). The sensor 34 specifies the air supplyto the engine. The throttle flap 16 is connected via a mechanicalconnection 38 to a position sensor 40 for detecting the position of thethrottle flap 16. The output line 42 of the position sensor 40 leads tothe control unit 32. The throttle flap 22 is also connected via amechanical connection 44 to a throttle flap position sensor 46 havingoutput line 48 leading to the control unit 32. The position sensors arepotentiometers in the preferred embodiment. Furthermore, the internalcombustion engine includes a rpm sensor 50 which is connected via a line52 to the control unit 32. In the exhaust-gas system 14 of the engine,at least one exhaust-gas sensor 54 is provided which is connected via aline 56 to the control unit 32. Furthermore, the control unit 32 hasfurther input lines 58 to 60 which connect the control unit 32 tomeasuring devices 62 to 64, respectively, for further operatingvariables of the engine and/or vehicle. The control unit 32 has the line66 as an output line. This output line connects the control unit to atleast one injection valve 30 for controlling the metering of fuel.Furthermore, an output line 68 is provided which leads to the electricmotor 26 for actuating the throttle flap 22. In addition to influencingthe metering of fuel and the throttle flap 22, an influencing of theignition angle (not shown for reasons of clarity) as well as a controlof the idle position of the throttle flap 16 is provided as required.

The above-described electrically actuable ancillary flap is in additionto the mechanically actuable main throttle flap. In addition to thisancillary flap, and in another advantageous embodiment (not shown forreasons of clarity), a so-called electronic accelerator pedal system isprovided wherein a single throttle flap is electrically adjusted independence upon the position of the accelerator pedal. The throttle flap16 is connected via a mechanical connection to an electrical positionmotor which is actuated by the control unit 32 via a drive line. Asignal for positioning the throttle flap is supplied to the control unit32 via the position transducer 40 and the line 42. The elements 68, 26,24, 22, 28, 44, 46, 48 of FIG. 1 can then be omitted.

In addition to the ancillary throttle flap or the electrical mainthrottle flap, in other advantageous embodiments individual throttleflaps are provided which influence the air supply to individualcylinders or throttle flaps can be provided for so-called channel cutoffwhich influences the air supply to a pregiven number of cylinders. Inaddition to the electrical actuation of the throttle flap, otherembodiments have been shown to be advantageous wherein the throttleflaps are actuated via a hydraulic or pneumatic path.

The control unit 32 forms a load signal from a characteristic field in amanner known per se in dependence upon the engine rpm supplied via theline 52 and the air mass supplied via the line 36. The load signal iscorrected at least by an exhaust-gas control and defines the injectionpulse for the injection valve 30. The injection pulse is outputted viathe line 66. The exhaust-gas control is a λ-control. An exhaust-gasprobe 54 is utilized which outputs a signal, which can be evaluated upto λ=1.6. This signal is outputted not only in the stoichiometric rangebut also in the lean range. Preferably, the exhaust-gas probe 54essentially exhibits a linear characteristic. The fuel metering systemis then adjusted in such a manner that the engine is operated with anexcess of air at least in the lower and mid part-load range. With thisoperation, λ preferably has a value in the region of 1.5. Duringtransient operation, when the driver accelerates (that is, in the upperpart-load range or full load range, when the power demand on the engineis high), a switchover is made from the lean operation to an operationhaving a stoichiometric mixture (λ=1). The change of the mode ofoperation takes place in accordance with the procedure of the inventionin that the fuel injection quantity is maintained constant, theexhaust-gas control is switched over from the desired value λm in thelean range to the desired value λ1 or vice versa and the torque changeresulting therefrom is compensated by a jump-like influencing of the airsupply or a jump-like adjustment of the throttle flap 16 or 22 dependingupon the embodiment.

FIG. 2 shows a realization of the control unit 32 for carrying out thedescribed procedure. The reference numerals described with respect toFIG. 1 are used. The control unit 32 includes a first computing unit ora first characteristic field 200 to which the lines 52 and 36 are led.The output line 202 of the unit 200 leads to a correction stage 204having an output line defined by line 66. The correction stage 204 isconnected via a line 206 to a λ-controller 208 to which an actual signalis supplied via the line 56 and a desired signal is supplied via line210. The line 210 leads from a switch element 212 to which the desiredvalue λ1 is supplied via line 214 and a desired value λ>1 is suppliedvia the line 216. The switch element 212 is switched via a line 218. Theline 218 is the output line of a computing unit or a characteristicfield 220. In the preferred embodiment, the line 42 (driver command) aswell as the lines 52, 36 as well as 58 to 60 are connected tocharacteristic field 220. The output line 218 leads to a furthercomputing unit (that is, a further characteristic field 222) to whichthe lines 42 and 52 are connected. The output line 224 of the unit 222leads to a computing unit or a characteristic field 226 or,alternatively, to a correction stage 228. The lines 42 and 52 lead tocharacteristic field 226. The output line 230 of characteristic field226 leads to a position controller 232. In addition, the line 48 leadsto the position controller 232 as does the line 42 when utilizing anelectronic accelerator pedal system. The output line 234 of the positioncontroller 232 leads, as required, via the correction stage 228 to theoutput line 68.

In the characteristic field 200, the control unit 32 forms a basic loadsignal t_(L) which is outputted via line 202 to the correction stage204. The base load signal t_(L) is formed in dependence upon the enginerpm (line 52) and the signal for the air mass, air quantity, intake pipepressure or the throttle flap position. This signal is supplied via theline 36. The correction stage 204 serves to correct the load signal orthe base injection signal t_(L) in dependence upon the output signal ofthe λ-controller 208. The λ-controller compares the actual value signalof the exhaust-gas probe 54 with the preadjusted desired value. In thepreferred embodiment, the exhaust-gas probe 54 exhibits an essentiallylinear characteristic line and, in other embodiments, the exhaust-gasprobe 54 exhibits a relationship between the exhaust-gas composition andits output signal. This relationship can be evaluated over the desiredrange. In accordance with a pregiven control strategy (for example,proportional-integral) and together with a precontrol dependent, forexample, upon the desired value, the controller 208 outputs an outputsignal on the line 206 which corrects the base injection signal t_(L) inthe sense of an approximation of the actual value to the desired value.The corrected signal forms the injection signal ti and is outputted vialine 66 to the one or more injection valves.

In at least the steady-state or quasi-transient operation in the lowerand mid part-load ranges, the λ-controller 208 is supplied with adesired value via the lines 216 and 210 because of a correspondingposition of the switch element 212. This desired value corresponds to alean air/fuel mixture. In the preferred embodiment, this desired valueis 1.5. For transient operating states, such as accelerations ordecelerations (during significant power requirements such as in or nearthe full-load range), the desired value of the λ-controller is set to 1by switching over the switch element 212. This improves the drivingperformance and a stoichiometric ratio between air and fuel massresults.

The switchover is triggered by the computing unit 220. This unitevaluates the following: accelerator pedal position and, if required,also the throttle flap position; the load signal; the transmissionposition and/or the engine rpm. This evaluation is made in order todetect a power command of the driver and derive therefrom the necessityfor a switchover of the λ-controller. This takes place in the simplestcase by inputting a threshold value for the accelerator pedal positionin the vicinity of the full load range (for example, at a 70°accelerator pedal position). A switchover to stoichiometric operationtakes place when this threshold value is exceeded.

The consideration of transmission position and engine rpm or of the loadsignal in combination with the accelerator pedal position or throttleflap position is likewise advantageous in that a command for a highengine torque is detected. Furthermore, the computing unit 220 candetermine and evaluate the time-dependent derivative of the acceleratorpedal position in order to detect transient operations. If thetime-dependent derivative exceeds a pregiven limit value (that is, isthe accelerator pedal actuated very rapidly in the direction ofacceleration), then this is an indication to switch over tostoichiometric operation.

The switchover from stoichiometric operation to lean operation takesplace with opposite signs. If the accelerator pedal position drops, forexample, below the pregiven threshold value, then there is a switch backto lean operation; likewise, when a detection is made based on theabove-mentioned parameters that only a slight torque is requested of theengine or when the time-dependent derivative of the accelerator pedalposition drops below the threshold value after a certain time haselapsed since the time point when this threshold value was exceeded.

The switch element 212 is actuated when the computation unit 220 detectsa power command of the driver. The desired value of the λ-controller isaccordingly changed in a jump-like manner; whereas, the injectionquantity is at first unaffected. In conventional systems, such a changeof the λ desired value because of a corresponding correction of theinjection time leads to a change in torque of the engine which is notwanted. For this reason, the switchover signal on the line 218 issupplied to the switch element 212 as well as to the characteristicfield 222. Because of the switchover signal, the characteristic field222 is activated and determines a throttle flap position on the basis ofthe instantaneously present accelerator pedal position and the enginerpm in correspondence to the direction of the switchover. The throttleflap position is outputted via the lines 224 and 230 to the positioncontroller which positions the ancillary flap based on the throttle flapposition value. In the position controller 232, the desired value iscompared to the actual value of the throttle flap position and an outputsignal is generated which adjusts the position of the ancillary throttleflap in the sense of a control to the desired value.

For a switchover from lean operation to the stoichiometric operation,this means a displacement of the throttle flap from its completely openposition to a specific throttle flap angle; whereas, in the reversesituation, the throttle flap is shifted into its completely openposition.

The extent of the adjustment of the throttle flap is then determined insuch a manner that a torque change of the engine takes place because ofthe throttle flap adjustment. This torque change compensates essentiallythe torque change caused by the switchover of the λ-controller. This isachieved via the characteristic field 222 wherein correspondingexperimentally determined values are stored for the extent of theadjustment of the throttle flap for each operating point (determined viathrottle flap position and engine rpm). For this purpose, for eachoperating point or for individual support points, the change of thetorque, which is generated by a specific adjustment of the throttleflap, is determined. When, for the λ control, only a switchover betweentwo fixed pregiven desired values is used for both modes of operation,the determination of the required throttle flap adjustment to compensatefor the torque change because of the switchover is sufficient for eachoperating point. For changing desired values, the determination for eachpossible desired value jump or for individual support positions ofdesired value jumps has to be carried out. The results are then enteredinto the characteristic field 222 in which the amounts for the throttleflap adjustment via accelerator pedal position and engine rpm areplotted as required as a function of the λ change.

In order to provide a torque compensation when switching over from thestoichiometric operation into the lean operation, the ancillary throttleflap is adjusted in stoichiometric operation in dependence upon theaccelerator pedal position and the engine rpm as well as, if required,in dependence upon the λ value to be adjusted in lean operation via thecharacteristic field 222 in such a manner that the torque change of aswitchover (which occurs at any desired time point) is compensated byadjusting the throttle flap in a position which is further open.

If an electronic accelerator pedal system is used, a characteristicfield 226 is provided which, in lean operation, determines a throttleflap position on the basis of accelerator pedal position and, ifrequired, on the basis of engine rpm. The position controller 232 thencontrols the throttle flap position over the entire operating range insuch a manner that the actual throttle flap position corresponds to thedesired value. In an embodiment of this kind, a switchover to thecharacteristic field 222 takes place in stoichiometric operation tocontrol the throttle flap. This characteristic field 222 is fixed withrespect to the characteristic field 226 in such a manner that thedifferences in the read out throttle flap positions compensate thetorque change generated by the λ switchover.

In another advantageous embodiment, the characteristic field 226 is notcontrolled by the characteristic field 222; instead, the characteristicfield values of the characteristic field 226 are corrected additively,multiplicatively or in another manner via the values read out from thecharacteristic field 222.

Furthermore, in a further advantageous embodiment, and proceeding fromcharacteristic field 222, the throttle flap is adjusted directly via thecorrection stage 228 independently of the position controller in thecontext of an open control. Here, the values read out of thecharacteristic field 222 either form corrective values for thecontroller output signal or replace this signal.

The embodiment described above switches between two fixed desired valuesof λ. In other embodiments, it can be advantageous to change the desiredvalue in the lean range because of toxic-substance emissions. In thiscase, the actual λ desired value is inputted into the characteristicfield 222 before and after the switchover so that a measure for thethrottle flap position change and therefore a measure for the torquecompensation can be obtained based on accelerator pedal position andengine rpm.

In FIGS. 3a to 3d, typical signal traces are shown for an exemplaryoperating situation. Time is plotted along the horizontal in each ofFIGS. 3a to 3d. In FIG. 3a, the λ value is plotted along the verticalaxis; in FIG. 3b, the accelerator position α is plotted and the airsupply Q_(L) is plotted in FIG. 3c. In FIG. 3d, the torque M of theengine is plotted also as a function of time.

Up to time point t₁, the engine runs in the lean range. A switchoverfrom the lean setting to the stoichiometric setting takes place when apregiven accelerator pedal threshold α₀ is exceeded. According to FIG.3a, this leads to a change of the λ value and, in accordance with FIG.3c, to a jump-like reduction of the air supply Q_(L). The torque amountsof the λ change and the change of the air supply are so selected thatthey essentially compensate each other. For this reason, no torquechange can be seen in FIG. 3d at time point t₁. At time point t₂, theaccelerator pedal position drops below the threshold value. This leadsto a switchover from the stoichiometric setting into the lean settingwhich leads to a jump-like change of the λ desired value at time pointt₂ and to a jump-like increase of the air supply Q_(L) at time point t₂as shown in FIGS. 3a and 3c. Here too, the torque amounts of bothchanges compensate each other so that for the course of the torque inaccordance with FIG. 3d, no or only very slight torque changes aredetected. The injection time ti remains unchanged during the transitionsbecause, as a consequence of the time constant of the λ control, theadaptation of the exhaust-gas composition to the change of the desiredvalue is undertaken via changes of the air supply (that is, by the jumpof the throttle flap). In this way, the λ control controls only smallchanges when the desired value changes.

In FIG. 4, a flowchart in the form of a computer program is shown as arealization of the procedure of the invention. After the start of thesubprogram, and in a first step 300, the following relevant operatingvariables are read in: accelerator pedal position α, engine rpm n, airsupply Q_(L), transmission ratio U, lambda value λ as well as throttleflap position DK. And, in the next step 302, the base injection time tiis determined by forming a quotient of the air supply and the enginerpm. Inquiry step 304 then follows.

In this inquiry step, a determination is made as to whether a powerrequest of the driver is present. This takes place, for example, by acomparison of the accelerator pedal position to a pregiven thresholdvalue, by evaluating the time-dependent derivative of the acceleratorpedal position, by combined evaluation of accelerator pedal position,engine rpm, engine load and/or transmission ratio, in order to determinean increased torque demand on the engine.

If a power command is detected, then in the following inquiry step 306,a check is made as to whether this power command occurred for the firsttime. If the power command occurred for the first time, then, in step308, the λ desired value is set to 1 and, in the next step 310, thedesired set value of the throttle flap is determined in accordance witha first characteristic field from accelerator position and engine rpm.This characteristic field is selected in such a manner that, for atransition from λ>1 to λ=1, the occurring torque jump is preciselycompensated by the corresponding adjustment of the throttle flap and thereduction of the air supply. If the throttle flap desired value isdetermined in accordance with step 310, then, in step 312, the throttleflap drive signal is determined by the position controller on the basisof the difference between desired and actual values. In the next step314, the injection time ti is determined on the basis of the baseinjection time t_(L) and the output of the λ-controller.

If, in step 306, it is detected that the power command has already beendetected in a previous program passthrough, then, in step 316, thethrottle flap desired value is determined on the basis of acceleratorpedal position and engine rpm in accordance with the firstcharacteristic field and the program continues with steps 312 and 314.

If no request for power is detected, then a check is made in step 318 asto whether this is the case for the first time. If this is the case,then in step 320, the λ desired value is set to a value>1 and, in thenext step 322, the throttle flap desired value is determined inaccordance with a second characteristic field on the basis ofaccelerator pedal position and engine rpm. Here too, the torque change,which is to be expected because of the change of desired value of theλ-controller, is compensated by a corresponding configuration of thesecond characteristic field in step 322. After step 322, step 324follows and the throttle flap drive signal is computed by the positioncontroller. If, in step 318, it is detected that no power command isdetected at least in the pregiven program passthrough, the programcontinues directly with step 322. The subprogram is ended after step 314and repeated at a pregiven time.

FIGS. 3a to 3d and 4 were explained on the basis of a so-called EGASsystem. If an ancillary flap is used in accordance with FIG. 1, then thesecond characteristic field in the right branch of the flowchart of FIG.4 is omitted. In lieu of this characteristic field, the drive for theancillary flap is switched off whereby the throttle flap is shifted intothe fully open position under the action of the return spring. Acorresponding procedure is carried out for individual throttle flaps orfor throttle flaps for switching off a channel.

We claim:
 1. A method for controlling an internal combustion enginehaving at least one electrically actuable adjusting element forcontrolling the air supply to the engine, the method comprising thesteps of:controlling the metering of fuel to the engine in accordancewith operating state present so that at least in a first operating rangean adjustment is made to provide a lean air/fuel ratio and in at least asecond operating range an adjustment is made to provide a stoichiometricratio; switching between said operating ranges pursuant to at least oneof the following:(a) in dependence upon the time-dependent derivative ofthe accelerator pedal position; (b) in dependence upon the acceleratorpedal position; and, (c) because of increased torque requirementdetermined in dependence upon at least one of the following:(i)accelerator pedal position; (ii) engine rpm; (iii) engine load; and,(iv) transmission ratio;and effecting said switching at least by actingupon said adjusting element for controlling the air supply to saidengine; setting said adjusting element in accordance with an input valuederived in dependence upon a driver command and by taking into account apregiven air/fuel ratio; forming said input value in dependence uponsaid accelerator pedal position and said engine rpm; changing saiddependence when there is a change of the pregiven air/fuel ratio so thatthe torque outputted by said engine before and after the switchoverbetween said operating regions is essentially the same; and, shiftingsaid adjusting element in a jump-like manner.
 2. The method of claim 1,wherein said adjusting element is shifted with a single jump.
 3. Themethod of claim 1, wherein said engine has a λ-controller forcontrolling the air/fuel ratio; and, wherein the method furthercomprises the step of changing the desired value of said λ-controllerfrom a value providing a lean mixture composition to a value providing astoichiometric composition when the switchover occurs from said firstoperating range having the lean air/fuel ratio to said second operatingrange having the stoichiometric ratio.
 4. The method of claim 1, whereinsaid adjusting element is an ancillary flap in the main channel of theair intake system or is assigned to individual ones or groups ofcylinders and, in lean operation, is in the fully open position and, instoichiometric operation, is adjusted in the direction of closing. 5.The method of claim 1, further comprising the steps of setting saidadjusting element during stoichiometric operation in accordance with afirst characteristic field and setting said adjusting element in leanoperation in accordance with a second characteristic field at least independence upon said accelerator pedal position.
 6. The method of claim1, wherein the adjusting element is adjusted in the context of aposition control.
 7. The method of claim 1, wherein an exhaust-gas probehaving a linear characteristic line is utilized for λ control.
 8. Themethod of claim 1, wherein the jump-like adjustment of the desired valueof the λ control and of the adjusting element for adjusting the airsupply to the engine take place simultaneously.
 9. An arrangement forcontrolling an internal combustion engine having at least oneelectrically actuable adjusting element for controlling the air supplyto the engine, the arrangement comprising:means for controlling themetering of fuel to the engine in accordance with operating statepresent so that at least in a first operating range an adjustment ismade to provide a lean air/fuel ratio and in at least a second operatingrange an adjustment is made to provide a stoichiometric ratio; means forswitching between said operating ranges pursuant to at least one of thefollowing:(a) in dependence upon the time-dependent derivative of theaccelerator pedal position; (b) in dependence upon the accelerator pedalposition; and, (c) because of increased torque requirement determined independence upon at least one of the following:(i) accelerator pedalposition; (ii) engine rpm; (iii) engine load; and, (iv) transmissionratio;and effecting said switching at least by acting upon saidadjusting element for controlling the air supply to said engine; meansfor setting said adjusting element in accordance with an input valuederived in dependence upon a driver command and an input value derivedby taking into account a pregiven air/fuel ratio; derivation means forderiving said input value for said adjusting element; said derivationmeans being configured so that said input value is dependent upon saidaccelerator pedal position and said engine rpm and so that, when thereis a change of the pregiven air/fuel ratio, the dependency upon saidaccelerator pedal position and said engine rpm is changed so that thetorque outputted by said engine before and after the switchover betweensaid operating ranges is essentially the same; and, means for shiftingsaid adjusting element in a jump-like manner.
 10. The arrangement ofclaim 9, wherein said adjusting element is shifted with a single jump.11. The arrangement of claim 9, wherein said adjusting element is afirst element for controlling the air supply to the engine and saidfirst adjusting element being adjustable mechanically by the driver;and, said arrangement further comprising a second element forcontrolling the air supply to the engine and said second adjustingelement being actuated in at least one of the following ways:electrically, pneumatically and hydraulically; and, said secondadjusting element being mounted in series with said first adjustingelement in the air intake system of said engine.